oseltamivir at a glance
Medicine class
Neuraminidase inhibitor antiviral
Usual role
Treatment or prevention of influenza in clinically appropriate situations
Taking with food
May be taken with or without food; food can reduce nausea and vomiting
Vaccination
Does not replace influenza vaccination
What is oseltamivir used for?
The selected products are licensed for influenza treatment and prevention in defined circumstances:
Treatment of typical influenza illness in adults and children, including full-term newborn infants, when influenza is circulating.
Prevention after contact with a clinically diagnosed influenza case in people aged one year and over.
In exceptional circumstances, seasonal prevention in people aged one year and over.
Post-exposure prevention in infants under one year only during a pandemic influenza outbreak.
How does oseltamivir work?
Oseltamivir is converted in the body to oseltamivir carboxylate, which blocks influenza neuraminidase. This enzyme helps newly formed virus particles leave cells and spread.
oseltamivir preparations and strengths
Capsule
Route: Oral
Strengths: 30 mg, 45 mg, 75 mg
Oral suspension
Route: Oral
Strengths: 6 mg/mL
How to take oseltamivir
Take oseltamivir as prescribed.
It can be taken with or without food; taking it with food may reduce stomach upset.
Swallow capsules with water. People unable to swallow them may use the oral suspension.
Shake the suspension before every use and measure it with the supplied oral dispenser, not a household spoon.
Give liquid slowly into the inside of the cheek while the person is upright, then clean and air-dry the dispenser.
Capsules may sometimes be opened and mixed with a small amount of sweet food to mask bitterness. Follow the product leaflet or pharmacist's instructions and give the whole mixture immediately.
oseltamivir side effects
Common or expected effects
- Nausea or vomiting
- Headache
- Stomach pain or indigestion
Get urgent medical advice
- Severe allergic reaction or facial, mouth or throat swelling
- Blistering, peeling or widespread severe rash
- Jaundice or other signs of liver injury
- Gastrointestinal bleeding
- Seizures, hallucinations, delirium, marked confusion or abnormal behaviour
oseltamivir in pregnancy
Influenza can cause more serious complications during pregnancy, so suspected flu warrants prompt medical assessment. Oseltamivir is generally the usual first-choice antiviral when treatment is indicated. Observational evidence has not shown clear fetal harm, although available data have limitations; the prescriber should assess expected benefits.
oseltamivir while breastfeeding
Oseltamivir can be used during breastfeeding when clinically indicated. Milk transfer appears negligible. For full-term, healthy infants, monitor as a precaution for vomiting, diarrhoea, irritability or altered sleep; seek specialist advice for premature or unwell infants.
oseltamivir interactions
Clinically significant interactions are generally unlikely, but relevant examples include:
Probenecid
Increases exposure to oseltamivir's active metabolite; consider the clinical context and renal function.
Renally secreted medicines with a narrow therapeutic margin, including methotrexate, chlorpropamide and phenylbutazone
Use with caution because competition for renal tubular secretion may alter exposure.
Live attenuated influenza vaccine given as a nasal spray
Influenza antivirals may reduce vaccine effectiveness, so administration timing should be coordinated with a clinician or pharmacist.
Common questions about oseltamivir
Answers are fully visible for fast scanning and source review.
What infection does oseltamivir treat?
It acts against influenza A and B. It does not treat illnesses caused by other viruses or bacteria.
Does oseltamivir replace the flu vaccine?
No. It does not replace assessment for seasonal influenza vaccination.
Can oseltamivir be taken with food?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.